the chance is more than remote. and the open can of pepsi was probably spiked with roofies or something like that.
knowing the nanny state, they also probably cooked a GPS chip into a piece of chicken for the guy to swallow, so they could track him in case he somehow slips away.
The ingenious thing to do would be to put something in the chicken thats guarenteed to give the guy the hershey squirts real fast - like a laxative. as crazy as the guy is, i bet he's not interested in having explosive diahreah in public on the roof.
but...if therese a chimminey.....he could use that....so X the laxative idea.